Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel the sweet potato and cut it into 1/2-inch cubes. Slice the red bell pepper into thin strips.
In a large bowl, toss the sweet potato cubes, broccoli florets, and bell pepper strips with 0.5 tablespoon of olive oil, half of the sea salt, half of the black pepper, and the dried oregano.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 20-25 minutes until the sweet potatoes are tender and the broccoli is slightly charred.
While the vegetables roast, season the chicken breast with the remaining sea salt, black pepper, and garlic powder.
Heat the remaining 0.5 tablespoon of olive oil in a cast-iron or stainless steel skillet over medium-high heat.
Place the chicken in the skillet and sear for 5-7 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden brown.
Remove the chicken from the pan and let it rest for 3 minutes before slicing.
Serve the sliced chicken alongside the roasted vegetables and finish with a fresh squeeze of lemon over everything.